Helicons - The early years

Helicon waves are right-hand polarized (RHP) waves which propagate in radially confined magnetized plasmas for frequencies omega(ci) much less than omega much less than omega(ce) where omega(ci) is the ion cyclotron frequency and omega(ce) is the electron cyclotron frequency, They are part of a much larger family of waves which can propagate down to zero frequency and constitute a very rich field for studying complex propagation characteristics and wave-particle interactions, This paper gives a historical perspective of the waves and their relationship to plasma source development up to the mid 1980's, presents a simple description of their propagation characteristics in free and bounded plasmas, and finishes with their first reported use in plasma processing experiments.